1. Field of the Invention
The invention relates a vehicular control apparatus.
2. Description of the Related Art
Electric power steering systems (EPS) are known which apply power of a motor to a steering mechanism of a vehicle to assist a driver's steering operation. Such a motor is controlled by a microcomputer. The microcomputer performs current feedback control to control driving of the motor in order to allow a current value of a current actually applied to the motor to track a current command value.
In some EPSs, a central processing unit (hereinafter referred to as a CPU) included in the microcomputer is duplicated in order to enhance safety and reliability. For example, an EPS described in Japanese Patent Application Publication No. 2013-159120 (JP 2013-159120 A) has a main CPU that mainly performs driving control of the motor and a sub CPU that monitors operations of the main CPU.
In some EPSs, instead of the CPU, the microcomputer is duplicated. A sub-microcomputer executes a process of resetting a main microcomputer if the main microcomputer becomes abnormal. To reliably execute the resetting process, the sub-microcomputer causes a quasi-abnormality in a signal from the main microcomputer that is a monitoring target signal during an initial check time at the time of switch-on of an ignition. When the signal from the main microcomputer is normalized as a result of the resetting process executed to eliminate the quasi-abnormality, whether a path on which the resetting process is executed functions normally is checked.
However, due to a constraint on the initial check time at the time of switch-on of the ignition in the vehicle, whether the resetting process is executed on all of the monitoring targets of the main microcomputer cannot be checked. Thus, paths on which the check for the resetting process is not executed fail to be checked for normal functioning.
In this case, even when an abnormality occurs in the main microcomputer becomes abnormal, the resetting process fails to be reliably executed on the main microcomputer. Thus, the main microcomputer may continue to be abnormal. Such a phenomenon is not limited to the microcomputer or CPU in the EPS but is common to control apparatuses mounted in vehicles.